Strong storms moved across far northern Illinois during the early morning hours of August 7th.
Every event with a place to put it. Tap one for its entry below.
Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The episode as NWS LOT wrote it up.
Strong storms moved across far northern Illinois during the early morning hours of August 7th.
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Chicago, IL wrote its last area forecast discussion before the first event at Aug 7, 4:20 AM CST, 40 minutes earlier.
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
520 AM CDT TUE AUG 7 2007
.DISCUSSION REGARDING MORNING GRIDS/ZONES...
330 AM CDT
MAIN FORECAST ISSUE IS SHORT TERM FLOODING. LARGE MCS WILL CONTINUE
TO AFFECT NORTHERN ILLINOIS THIS MORNING. HOURLY RAINFALL RATES OF
AROUND 3 INCHES/HOUR HAVE BEEN REPORTED ACROSS NORTHERN TIER OF
COUNTIES ACROSS FAR NORTHERN ILLINOIS WITH EXTENSIVE FLOODING
PROBLEMS. CONVECTIVELY ENHANCED SHORTWAVE WHICH AIDED IN MCS
FORMATION WILL TRACK THROUGH SOUTHERN WISCONSIN AND INTO LOWER
MICHIGAN THIS AFTERNOON. SHOULD GRADUALLY SEE DISSIPATING TREND TO
THIS MCS THROUGH THE MORNING HOURS...ALTHOUGH SEVERAL MORE HOURS OF
HEAVY RAINFALL ACROSS NORTHERN SECTIONS OF THE CWA WILL BE LIKELY.
OUTFLOW BOUNDARY FROM THIS ACTIVITY WILL LIKELY BECOME THE EFFECTIVE
SYNOPTIC FRONT THIS AFTERNOON...LIKELY STALLING OUT SOMEWHERE NEAR
INTERSTATE 80. MAY SEE ADDITIONAL DIURNALLY ENHANCED ACTIVITY FORM
ON THIS BOUNDARY THIS AFTERNOON AND HAVE SLIGHTLY REORIENTED POPS TO
REFLECT THIS BEST GUESS AS TO BOUNDARY LOCATION/CONVECTIVE
INITIATION THIS AFTERNOON. IMPRESSIVE INSTABILITY AGAIN THIS
AFTERNOON WITH 2000 J/KG OF MLCAPE BUT MAY NOT HAVE A MID/UPPER
LEVEL FORCING TRIGGER TO INITIATE CONVECTION. DEEP LAYER SHEAR
PROFILES ARE SUFFICIENT FOR SEVERE THREAT FOR AFTERNOON
CONVECTION...AND GIVEN VERY HIGH FREEZING LEVELS MAIN THREAT SHOULD
BE CONFINED TO WINDS.
GIVEN TRACK OF CURRENT MCS HAVE OPTED TO SHAVE A ROW OF COUNTIES OFF
THE SOUTHERN PORTIONS OF THE FLASH FLOOD WATCH. OTHER CONCERN TODAY
WILL BE COMBINATION OF HEAT/HUMIDITY ACROSS FAR SOUTHERN PORTIONS OF
THE FORECAST AREA. DEW PTS IN THE UPPER 70S SHOULD ALLOW FOR HEAT
ADVISORY CRITERIA TO BE MET THIS AFTERNOON AND AGAIN ON WEDNESDAY
AFTERNOON. WILL ISSUE HEAT ADVISORY FOR FAR SOUTHERN COUNTIES
THROUGH WEDNESDAY AFTERNOON.
HAVE NOT MADE MANY CHANGES TO THE FORECAST THIS MORNING...WITH
CHANCES OF PRECIP APPEARING ON TRACK THROUGH THURSDAY. BEST CHANCE
OF ADDITIONAL SHOWERS AND THUNDERSTORMS LOOKS TO BE WEDNESDAY NIGHT
INTO THURSDAY WITH ANOTHER MCS POSSIBLY MOVING INTO NORTHERN
ILLINOIS AT THIS TIME.
MARSILI
&&
.AVIATION...
1259 AM CDT
FOR 06Z TAFS...CONVECTION TRENDS/MCS DVLPMNT AND PROPAGATION THROUGH
MORNING HOURS MAIN CONCERN...ALONG WITH ASSOCIATED VIS/CIG CONCERNS.
LATEST SFC ANALYSIS INDICATES NEARLY STATIONARY FRONTAL BOUNDARY
DRAPED FROM NERN IA...SW WI...TO IL/WI BORDER AREA FAR NERN IL. MID
LVL S/WV TROF NOTED IN VAPOR IMAGERY ACROSS MN/WRN IA...INDUCING
30-40 KT SWLY LLVL JET INTO BAROCLINIC BOUNDARY FROM IA EASTWARD
INTO SRN WI/NRN IL. LLVL JET PROGGED TO VEER MORE WSW WITH TIME NEXT
SVRL HRS...SUGGESTING FOCUS OF STRONG MOIST ADVECTION/CONVERGENCE TO
CONTINUE TO SHIFT EAST ACROSS NRN IL THROUGH SUNRISE. THIS EXPECTED
TO AFFECT ALL TERMINAL SITES...WITH TSRA/IFR CONDITIONS EXPECTED.
EXPECT MAIN ROUND OF TSTMS TO AFFECT KRFD 07-11Z...AND CHI AREA
TERMINALS 08-12Z...THOUGH WILL LIKELY SEE ADDITIONAL WEAKER SCT
RW/TRW DVLPMNT INTO MID MORNING HOURS IN CONTINUED WESTERLY LLVL
WAA/MOIST ADVECTION. THUS HAVE CARRIED VCTS/TEMPO SHRA FOR MUCH OF
REMAINDER OF MORNING HOURS. S/WV AND ASSOCIATED SFC LOW PRESSURE
WAVE MOVE NORTH OF FCST AREA BY MIDDAY...WITH SFC FRONT SAGGING BACK
SOUTH ACROSS TERMINALS LATE MORNING/EARLY AFTN. MODEL TSECTS
INDICATE DRYING IN MID LVLS BY AFTN...WITH WEAK SUBSIDENCE INVERSION
NOTED AROUND 700 HPA IN FCST SNDGS. WITH RICH BOUNDARY LAYER
MOISTURE INSTABILITY REMAINS A CONCERN...WITH 3000+ J/KG MLCAPE
NOTED IN WRF SOUNDINGS MID/LATE AFTN. EXPECT THAT LLVL CONVERGENCE
ALONG FRONTAL BOUNDARY TO BE SOUTH OF TERMINALS BY THAT TIME
HOWEVER...SO HAVE GONE DRY FOR TAFS THIS AFTN. ULTIMATE LOCATION OF
BOUNDARY WILL PLAY ROLE IN HOW GREAT CONVECTIVE THREAT BECOMES THIS
AFTN AT TERMINAL SITES...THOUGH CONFIDENCE LOW ATTM.
AS FOR WINDS...LGT/VRBL WINDS IN WEAK SFC PRESSURE GRADIENT VCNTY
STATIONARY FRONT ATTM...WILL ONLY BECOME MORE VRBL AS WIND FIELD
BECOMES MORE CONVECTIVELY DISTURBED NEXT SVRL HRS. TRIED TO
INDICATE MORE OF A SYNOPTIC WSW LATER THIS MORNING WITH SHIFT TO
WNW LATE.
RATZER
&&
.MARINE...
520 AM CDT
LOW PRESSURE OVER IOWA THIS MORNING WILL LIFT NORTHEAST ACROSS THE
WESTERN GREAT LAKES REGION TODAY. A COLD FRONT TRAILING FROM THIS
LOW WILL SAG SOUTH OF THE LAKE BY TONIGHT...BEFORE WEAK HIGH
PRESSURE BUILDS ACROSS THE NORTHERN LAKES ON WEDNESDAY. ANOTHER AREA
OF LOW PRESSURE WILL MOVE FROM THE PLAINS...JUST SOUTH OF LAKE
MICHIGAN ON THURSDAY. HIGH PRESSURE WILL THEN ONCE AGAIN BUILD
ACROSS THE NORTHERN LAKES FRIDAY AND SATURDAY.
RATZER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...HEAT ADVISORY IN EFFECT THIS AFTERNOON THROUGH
WEDNESDAY AFTERNOON FOR LIVINGSTON...FORD...AND IROQUOIS
COUNTIES.
FLASH FLOOD WATCH MAINLY NORTH OF INTERSTATE 88 THROUGH NOON.
IN...HEAT ADVISORY IN EFFECT THIS AFTERNOON THROUGH WEDNESDAY
AFTERNOON FOR JASPER...NEWTON...BENTON COUNTIES FROM
THIS AFTEROON THROUGH THURSDAY AFTERNOON.
LM...NONE.
&&HAZARDOUS WEATHER OUTLOOK...CORRECTION NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL 430 AM CDT TUE AUG 7 2007 ILZ003>006-008-010>014-019>022-023-032-033-039-INZ001-002-010-011- 019-080930- WINNEBAGO-BOONE-MCHENRY-LAKE IL-OGLE-LEE-DE KALB-KANE-DU PAGE-COOK- LA SALLE-KENDALL-GRUNDY-WILL-KANKAKEE-LIVINGSTON-IROQUOIS-FORD- LAKE IN-PORTER-NEWTON-JASPER-BENTON- 430 AM CDT TUE AUG 7 2007 THIS PORTION OF THE HAZARDOUS WEATHER OUTLOOK IS FOR NORTH CENTRAL AND NORTHEAST ILLINOIS...AND NORTHWEST INDIANA. .DAY ONE... TODAY AND TONIGHT A FLASH FLOOD WATCH REMAINS IN EFFECT THROUGH 1 PM THIS AFTERNOON FOR FAR NORTHERN ILLINOIS. VERY HEAVY RAIN HAS FALLEN ACROSS PORTIONS OF NORTHERN ILLINOIS OVERNIGHT...MAINLY NORTH OF INTERSTATE 80. RUNOFF FROM THESE THUNDERSTORMS AND ADDITIONAL THUNDERSTORMS MOVING THROUGH THE AREA THIS MORNING WILL CONTINUE TO PRODUCE A POTENTIAL FOR FLASH FLOODING. THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE ENTIRE OUTLOOK AREA THIS AFTERNOON. THE MAIN THREAT WILL BE DAMAGING WINDS AND LOCALIZED HEAVY RAINFALL. THE CHANCE OF THUNDERSTORMS WILL CONTINUE INTO THIS EVENING MAINLY SOUTH OF INTERSTATE 80. THE COMBINATION OF HOT TEMPERATURES AND HIGH HUMIDITY WILL PRODUCE PEAK AFTERNOON HEAT INDEX READINGS OF AROUND 105 DEGREES THIS AFTERNOON ACROSS IROQUOIS...FORD...AND LIVINGSTON COUNTIES IN NORTHERN ILLINOIS ALONG WITH JASPER...NEWTON...AND LAKE COUNTIES IN NORTHWEST INDIANA. A HEAT ADVISORY IS IN EFFECT FOR THESE COUNTIES FROM THIS AFTERNOON THROUGH WEDNESDAY AFTERNOON. .DAYS TWO THROUGH SEVEN... WEDNESDAY THROUGH MONDAY THERE IS A CHANCE OF THUNDERSTORMS WEDNESDAY AND THURSDAY. A HEAT ADVISORY WILL REMAIN IN EFFECT THROUGH WEDNESDAY AFTERNOON FOR FORD...IROQUOIS...AND LIVINGSTON COUNTIES IN NORTHERN ILLINOIS AND LAKE...JASPER...AND NEWTON COUNTIES IN NORTHWEST INDIANA. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION MAY BE NECESSARY TODAY. REPORTS OF FLOODING AND RAINFALL AMOUNTS WILL ALSO BE MUCH APPRECIATED TODAY. && COMPLETE FORECAST INFORMATION IS AVAILABLE ON THE NWS CHICAGO WEBPAGE: WEATHER.GOV/CHICAGO (LOWER CASE) LMZ740>745-766-080930- WINTHROP HARBOR IL TO MICHIGAN CITY IN- LAKE MICHIGAN- 430 AM CDT TUE AUG 7 2007 THIS PORTION OF THE HAZARDOUS WEATHER OUTLOOK IS FOR THE ILLINOIS AND INDIANA WATERS OF LAKE MICHIGAN. .DAY ONE... TODAY AND TONIGHT THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON. THE MAIN THREAT WILL BE DAMAGING WINDS IN EXCESS OF 35 KNOTS. .DAYS TWO THROUGH SEVEN... WEDNESDAY THROUGH MONDAY THERE IS A CHANCE OF THUNDERSTORMS AGAIN WEDNESDAY NIGHT AND THURSDAY. && COMPLETE FORECAST INFORMATION IS AVAILABLE ON THE NWS CHICAGO WEBPAGE: WEATHER.GOV/CHICAGO (LOWER CASE) MARSILI
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
342 AM CDT TUE AUG 07 2007
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0200 AM FLASH FLOOD ROCKFORD 42.27N 89.06W
08/07/2007 WINNEBAGO IL LAW ENFORCEMENT
APPROXIMATELY 20 INTERSECTIONS FLOODED...6 CARS STRANDED
IN CITY OF ROCKFORD. FROM 911 CENTER.
0322 AM HEAVY RAIN ROCKFORD 42.27N 89.06W
08/07/2007 M4.83 INCH WINNEBAGO IL CO-OP OBSERVER
4 HOUR RAINFALL...SINCE 11 PM MONDAY EVENING.
0325 AM FLASH FLOOD WOODSTOCK 42.31N 88.44W
08/07/2007 MCHENRY IL TRAINED SPOTTER
INTERSECTION OF ROUTES 47 AND 120 SHUT DOWN DUE TO 2 FEET
OF STANDING WATER. WILLOW AND CLAY STREET SHUT DOWN DUE
TO WAIST DEEP WATER. PLOICE CONDUCTING RESCUES FROM
STRANDED VEHICLES. WATER A FOOT DEEP ON WASHINGTON
STREET.
&&
RATZERPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
434 AM CDT TUE AUG 07 2007
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0305 AM HEAVY RAIN 1 W BEACH PARK 42.42N 87.88W
08/07/2007 M1.02 INCH LAKE IL PUBLIC
COCORAHS OBSERVER
0405 AM HEAVY RAIN 1 NNW BARTLETT 41.99N 88.21W
08/07/2007 M1.56 INCH COOK IL PUBLIC
COCORAHS OBSERVER
&&
ACSPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
521 AM CDT TUE AUG 07 2007
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0518 AM HEAVY RAIN MARENGO 42.25N 88.60W
08/07/2007 M5.10 INCH MCHENRY IL CO-OP OBSERVER
RAINFALL SINCE 11 PM
0518 AM HEAVY RAIN WOODSTOCK 42.31N 88.44W
08/07/2007 M4.35 INCH MCHENRY IL CO-OP OBSERVER
&&
ACSThe Milwaukee radar (KMKX), 82 km away, was scanning. The volume nearest the first event began at 10:59 UTC.
1 thunderstorm wind. Local standard time, as filed.
A tree was blown down onto a tent with two people sleeping inside at Illinois Beach State Park. One person was killed and the other was injured.
As the offices recorded each death: direct deaths were caused by the weather itself, indirect ones by something it set in motion.
| Event | Date | Age | Sex | Where | Kind |
|---|---|---|---|---|---|
| Thunderstorm Wind, Lake | 2007-08-07 | 56 | Female | Camping | Direct |
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Illinois in 2007Every state in 2007This day in weather historyWarnings in Illinois, August 2007
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 54938.